package syntaxtree;import java.util.Vector;public class ExpList {   private Vector list;   public ExpList() {      list = new Vector();   }   public void addElement(Exp n) {      list.addElement(n);   }   public Exp elementAt(int i)  {       return (Exp)list.elementAt(i);    }   public int size() {       return list.size();    }}